Flood irrigation differs significantly from the practice of inhaling an atomized mist into the nose. During flood irrigation, the vast majority (>95%) of fluid taken in is expelled immediately (or shortly thereafter) after the contaminants have been rinsed out. Rinsing with flood irrigation is commonly performed by ingesting the liquid solution into one nostril and concurrently expelling the solution from the other nostril. Alternately, flood irrigation is sometimes performed by ingesting the liquid solution into both nostrils simultaneously and having the excess flow to the mouth. Flood irrigation has been demonstrated to be more effective than mist for the distribution of medications and the physical rinsing of the mucus membranes of the nose and sinuses. A user of nasal flood irrigation may typically use the technique once or twice per day as opposed to a user applying a mist several to many times a day.
The use of flood irrigation to cleanse, soothe and rehabilitate nasal and sinus passages has a long history which probably began with the practice of intentional inhalation of sea water from cupped hands. Later devices such as the Neti Pot made the practice more practical. Today there is a wide array of devices and technologies to facilitate the rinsing by flood irrigation of the nasal passages and sinus cavities. Investigation of prior art shows that the number of relevant devices and techniques has grown at an increasing rate in recent decades and in particular during the last ten years. This growth in technology has paralleled the increasing popularity of the practice as the technology has become more effective and as the benefits of the practice have become more appreciated.
Within the field of flood irrigation for nasal rinsing there are developments in the liquid solutions being used and there are developments in the device which delivers the liquid stream. The liquid delivery devices for nasal flood irrigation may be generally divided into two major commercial categories—a) simple devices which dispense a continuous low pressure stream of fluid from a squeeze bottle, deformable bulb, bellows container, shower head connection, gravity feed, etc., and b) devices which use a motorized pump or other complex and expensive electromechanical apparatus to provide a pulsating stream of fluid. Both categories of device have advantages and disadvantages.
The devices which dispense a continuous low pressure stream of irrigant typically are very low in cost and may have advantageously high flow rate capability. Unfortunately, these devices offer a less than optimal cleaning ability due to the tendency of the continuous stream to form laminar flow paths across the surfaces to be rinsed and due to the surfaces not being deformed and agitated by the smooth flow stream. These continuous stream devices are also ineffectual in projecting liquid medications or irrigants into sinus cavities because the closed end cavities require time varying pressures to cause fluid entry. They also fail to rehabilitate nasal cilia which have lost motility.
The pulsating electromechanical devices have the advantages of causing a much more turbulent scouring flow with high shear stress gradients along the surfaces, causing a mixing action to reduce surface based concentration gradients and deformations of the surfaces being rinsed (for flexible surfaces) and healthy movement of the nasal cilia. Pulsating electromechanical devices unfortunately offer a less than optimal flow rate. Additionally, the pulsatile electromechanical devices are significantly more complex and costly, with purchase cost approximately ten times that of a squeeze bottle irrigator. This high cost prevents many potential users from purchasing them and does not favor the periodic disposal of the device which is necessary to avoid colonization by bacteria and molds.